Study on risk assessment of metals and metalloids used in high technology industry

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This study consists of two Parts, which are i) toxicity assessment of gallium (Ga), Indium (In), and arsenic compounds used in semiconductor, and ii) yttrium (Y) and lanthanum used in superconductor.Aoki and Fowler estimated the renal toxicity of materials for semiconductors. Alterations in protein synthesis in primary cultures of rat kidney proximal epithelial cells were examined following exposure to Ga, In and sodium arsenite. Synthesis of seven proteins was markedly stimulated by exposure to 300 micro-M GaCl_3 or 10 micro-M arsenite. No significant changes in protein synthesis were observed with 300 micro-M InCl_3 exposure. Release of lactate dehydrogenese (LDH) from the cells was not significantly increase by exposure to concentration of 300 micro-M Ga and 3 micro-M arsenite or less. In the absence of overt cell injury, the induction of these proteins may be useful as an early indicator for exposure to Ga.Fowler at al. reported the effect of arsine exposure on pregnancy and prenatal development of mice and rats. Arsine gas was known to be a potent hemolytic agent. However, arsine at atmospheric concentrations that caused increases in maternal spleen size and measurable levels of arsenic in maternal blood and fetal livers did not adversely affect endpoints of developmental toxicity.Hirano and Suzuki examined the toxic effect of materials for superconductors on the lung. YCl_3 was instilled intratracheally into rats. Pulmonary clearance of Y was very slow and the halflife was estimated to be 168 days. Transmission electron microscopy and X-ray microanalysis suggested that Y was localized in lysosomes of alveolar and interstitial macrophages, and basement membranes. Comparative dose-effect profiles of LDH activity in bronchoalveolar lavage fluid supernatant revealed that 1 mol of YCl_3 is equivalent to about one-third mole of cadmium compounds and about 3 mol of zinc oxide in the potency for acute pulmonary toxicity.